Bj. Ginn et Tg. Gooch, TOUGHNESS OF 12-PERCENT-CR FERRITIC MARTENSITIC STEEL WELDS PRODUCED BY NON-ARC WELDING PROCESSES/, Welding journal, 77(8), 1998, pp. 341-349
Low carbon 12%Cr steels can offer reduced life cycle costs in many app
lications. The present work examined the behavior of commercial steels
of varying composition when subject to low heat input welding by the
electron beam (EB) process and to a forge cycle by linear friction wel
ding (LFW). Charpy impact testing was carried out on the high temperat
ure heat-affected zone (HAZ)/ fusion boundary or weld interface, with
metallographic examination. With EB welding, the ductile-brittle trans
ition temperature (DBTT) was below 0 degrees C (32 degrees F) only for
steel of low ferrite factor giving a fully martensitic weld area. Hig
her ferrite factor alloys showed predominantly ferritic transformed mi
crostructures and a transition well above room temperature. Grain coar
sening was found even with low EB process power, the peak grain size i
ncreasing with both heal input and steel ferrite factor. Use of LFW ga
ve a fine weld area structure and DBTTs around 0 degrees C even in hig
h ferrite factor (FF) material.